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Friction stir welding on the London underground

Case Study

Over 376 friction stir welded (FSW) vehicles have been ordered from Bombardier for the latest Victoria Line upgrade.

The process is being used to join stiff longitudinal extrusions which constitute the carbody's sidewalls. The welding is sub-contracted to Swedish supplier Sapa Profiler, who hold a TWI friction stir welding licence.

FSW is likely to be used on future contracts for over 2200 more new trains in the next decade. This work stems from the successful introduction, some time ago, of friction stir welding on the lower bodyside panels of mainline trains. The technological and commercial advantages of the process were studied and found favourable by Bombardier and London Underground.

Bombardier first showed interest in friction stir welding 11 years ago and Bombardier became a member of the first TWI Group Sponsored Project and has subscribed to several similar projects since then. After a three year process review by Bombardier the manufacturer introduced friction stir welding onto its Electrostar range of vehicles for the UK market.

It is now pursuing its research into friction stir welding through both internal and European projects which are geared towards improving the crash-worthiness of today's rail vehicles throughout Europe.

For more information about Friction Stir Welding, please contact us.